A medical advisory panel has moved the weight loss drug Qnexa one step closer to approval by the Food and Drug Administration.  A final ruling will not be made by the FDA until later this year, but it is expected that the Administration’s decision will follow the committee’s recommendations.

The drug, the first to be be potentially available by prescription since 1999, was rejected by the same advisory panel in 2010 because its poorly-understood cardiovascular side effects and risk of birth defects outweighed its benefits. 

Qnexa uses topiramate, an anti-seizure and migraine drug that has been investigated for the treatment of mood instability, and the appetite suppressant phentermine to aid in weight loss.  If approved, people with a body mass index of 30 or above -- considered obese -- would be prime candidates for the medication, reports the Los Angeles Times. 

From Business Week:

More than one-third of U.S. adults are obese, and another third are overweight, according to the Centers for Disease Control and Prevention. The obesity rate among adults has more than doubled since 1980 to 72 million people. 

Manufactured by Vivus, Inc., the drug continues to raise the concern of regulators because it increases the heart rate of patients who use it, exacerbating chances for heart attack and stroke.  An uptick in the risk of birth defects was also detected in women who took Qnexa during pregnancy; cleft lip was the most common defect noted.  

It is the drug’s excellent results -- 10 percent of total body weight loss in the first year of use, and improvements in blood pressure -- and additional regulatory stipulations, that led to the panel’s approval, said the Times report.

“Of all the obesity drugs, this one has the highest efficacy in terms of weight loss, so that shifts the balance in terms of requiring a post-approval study rather than a pre- approval study,” said panel member and UCLA Cedar Sinai Medical Center cardiology professor Sanjay Kaul.  Women who take the drug will be required to undergo monthly pregnancy testing, and healthcare providers will receive training on the risks and benefits of Qnexa (Los Angeles Times).  

“Vivus has suggested restricting distribution of Qnexa to less than 10 large mail-order pharmacies with pharmacists trained in dispensing the drug,” senior director of Vivus global medical affairs Barbara Troupin said.  "We will know who the prescribers are. We will know who has been trained.  We are confident the Qnexa [risk management program] balances the safeguards while allowing access for appropriate patients." (Business Week) 

Dr. Michael S. Lauer, director of the division of cardiovascular sciences at the National Heart, Lung and Blood Institute and a member of the advisory panel, was one of two dissenters voting against approval of the weight-loss drug.  He suggested that the manufacturer conduct further studies to determine the full extent of cardiovascular risk to patients.  Otherwise, he said in the Los Angeles Times report, FDA approval "would be a decision based on hopes, surrogates and suppositions."

"We have seen many cases in medicine where we thought we understood the pathology of disease … and we turned out to be wrong," Lauer said. "With an epidemic as serious as obesity, we need to do this right."